Accumulating evidence supports that more pain, whether measured by number of pain sites or pain severity, is associated with poorer cognitive function and mobility, and fall risk in older persons. The attentional burden of pain may be a factor in the high rate of falls among older persons who have chronic multisite pain. Tai Chi which holistically integrates physical and cognitive functions offers the possibility not only of alleviating pain but also improving attention and mobility in the many older adults who have chronic multisite pain. This proposed pilot study of a Tai Chi intervention among older adults with multisite pain is a direct extension of our current work examining attentional demands of chronic pain in the older population. The main purpose of this randomized controlled trial is to assess the feasibility and acceptability of a 12-week Tai Chi program for older adults with chronic multisite pain and a history of falling. We will examine the effects of Tai Chi on pain characteristics, cognitive function, cognitively-mediated mobility, and levels of pain-related biomarkers in community-dwelling older adults with multisite pain and at least one fall in the past year (65 years and older, N=30 for Tai Chi group and N=30 for mild exercise control group). Our specific aims for this R21 developmental grant application are: 1) to assess the feasibility and acceptability of a 12-week randomized controlled Tai Chi program in preparation for a larger trial in community-residing older adults. Specifically, we will: 1A) Evaluate the feasibility of recruitment and engagement of older adults who have chronic multisite pain in a 12-week Tai Chi intervention; 1B) Determine the optimal Tai Chi/exercise protocol and data collection protocol for planning a larger trial; 1C) Assess the adherence of randomized participants to their assigned treatment; 1D) Obtain information on differences in outcome measures and variations to be used for power analysis in a larger trial. 2) To examine the efficacy of Tai Chi on pain characteristics, pain-related biomarkers, cognitive function and cognitively-mediated mobility. Specifically, we will: 2A) Determine the effects of Tai Chi on measures of pain severity and pain interference; 2B) Determine the effects of Tai Chi on performance in tests of attention and executive function; 2C) Determine the effects of Tai Chi on performance in complex mobility tasks (dual task gait measures); 2D) Determine the effects of Tai Chi on levels of C-reactive protein (CRP), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-), and beta endorphin (-endorphin). This study will provide novel insights into the effects of a non-invasive behavioral intervention, Tai Chi, on chronic multisite pain and the associated cognitive-motor functions in older adults. The results of this exploratory study will provide critical pilot data that will guid and inform a larger randomized controlled trial designed to establish the clinical significance of Tai Chi on chronic multisite pain in older adults and to investigate the mechanisms by which Tai Chi may improve chronic pain and pain-related cognitive-motor functions using brain imaging and human genetic approaches.